#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>

int main()
{

    printf("before:  进程%d执行。。。\n ",getpid());

    pid_t id = fork();
    if(id  == -1)
    {
        printf("error\n");
        return -1;
    }

    printf("after:  进程%d执行。。。\n",getpid());
   return 0;
}
